Treating hides or skins.



UNIT STATES PATENT OFFICE.

SAMUEL K. FELTON, JR, on PHILADELPHIA, PENNSYLVANIA.

TREATING HIDES OR SKINS.

SPECIFICATION forming part of Letters Patent No. 721,553, dated February 24:, 1 903. Application filed May 1,1902- Serial No, 105,482. (N0 p imen To all whom it may concern:

Be it known that'I, SAMUEL K. FELTON, J r., a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain Improvements in Treating Hides or Skins, of which the followingis aspeciflcation.

The'object of my invention is to so conduct the process of unhairing hides or skins (including in this term the treatment preceding puring or hating that said process will be improved and shortened and the hides or skins will be in better condition than usual for the bating and subsequent treatments and the finishedleather will be tougher, stronger, and cleaner than leather produced from hides or skins treated by the processes now in use.

My invention is applicable to the treatment of hides or skins generally of the class usually employed in the preparation of light leather for the uppers of boots and shoes and like uses; but for convenience I will hereinafter use the term skin to indicate the same.

In carrying out my invention I first soak and mill the skins in the usual manner, and then for an ordinary pack of about six hundred pounds I slake one hundred and fifty pounds of lime, and during the process of slaking and while the lime is still hot I add twenty-four pounds of red arsenic and thoroughly stir the mixture, to which after the same is cool I add water until it assumes the consistency of thin paste or cream. Each skin is then spread out and treated on the flesh side with the compound thus produced, after which said skins are placed in a pile, flesh to flesh, and allowed to remain for about twenty-four hours, at which time the hair is so loosened that it can be readily removed from the skin either by hand or machine.

The treatment of the flesh side of the skin may be eifected by painting or daubing the same with the lime-and-arsenic compound if the sameis in the form of a paste or by passing the flesh side of the skin in contact with the compound if the latter is in fluid condi-- tion, and the skins may be packed with the flesh side of one against that of another, or each skin may be folded with the flesh side in.

When the preservation of the hair or fleece in good condition is not important, the application of the liming compound to the flesh side of the skin only need not be adhered to.

After being unhaired the skins are placed in a closed drum, into which is introduced a solution consisting of ninety pounds of sulfid of sodium (Na s) dissolved in a few gallons of hot water, to which is then added enough water to make one hundred and fifty gallons, the temperature of the solution being preferably from 90 to 100 Fahrenheit. The

drum is then rotated for about two hours, af-

ter which the skins are removed and stacked in a pile, in which condition they are permitted to remain for about twenty-four hours, and are then without washing removed to a receptacle and there subjected to the action of a solution of hyposulfite of soda or its cquiva1entsuch as sulfite, bisulflte, &c. and after being thoroughly stirred about in such solution for a short time are permitted to remain therein for about twenty-four hours. In preparing this solution I dissolve ninety pounds of commercial hyposulfite of soda (sodium thiosulfate Na S O in sufficient water to dissolve the same and then add water sufflcient to increase the solution to two hundred and twenty-five gallon s, the temperature of the solution being preferably about Fahrenheit. By thus immediately following the sulfid-of-sodium treatment with the hyposulflte-of-soda treatment I secure all of the beneficial action of the sulfld-of-sodium without any of its undesirable results.

The stock after the sulfid-of-sodium treatmentis swollen to its fullest extent, the fibers of the skins being difierentiated into finer fibrils and the stock thoroughly opened up, the natural fat of the skins being converted into a soluble soap, which can be subsequently washed out.

By subjecting the skins to the action of a sulfid-of-sodium solution after the same have a relatively weak sulfid solution, which will eliect the desired plumping of the skin without injurious action upon the tissues.

After the hyposulfite treatment the skins are fleshed by hand or machine and then placed in a vat which contains for each six hundred pounds of stock two hundred and ten pounds of lime and four and one-half pounds of red arsenic dissolved, as described before,in a suitable amount of water,in which bath the skins remain forfrom two to five days,

more or less, depending upon the character of the skins, after which they are removed, washed, pured, bated, drenched, or otherwise treated as may be necessary to prepare them for tanning.

The hyposullite treatment following the treatment with the sultid of sodium has the effect of neutralizing the sulfid remaining in the skin and preventing injury to the same by any subsequent washing to which it may be subjected. Such treatment, however, has the effect of leaving the skins in a condition which prevents the proper action thereupon of the pure or hating compound sub sequently applied thereto. This resistance to the action of the pure or bating compound I consider to be due to the presence of sulfur compounds in the skin, and the subsequent treatment with lime and arsenic has the effect of removing or so diminishing these sulfur compounds that the objection due to their presence is overcome.

I have found that the proportions of materials which I have given, the temperatures prescribed, and the time of the various treatments noted give the best results; but I do not wish to limit myself thereto, as all of these factors may be modified to a considerable extent without departing from the main purpose of my invention.

Skins treated in accordance with my invention preparatoryto tanning can be finished into what are known as fancy colors with much better result than skins which have been subjected to the ordinary treatment preceding the treatment with the pure or hating compound.

Having thus described my invention, I claim and desire to secure by Letters Patent 1. The within-described improvement in treating skins, which consists in subjecting them, after being limed, and unhaired, to the action of a sodium-sultid bath, and then to a hyposulfite-of-soda solution, substantially as specified.

2. The within-described improvement in treating skins which consists in subjecting them, after being limed and unhaired, to the action of a sodium-sulfid bath, then to a hy-' posulfite-of-soda solution, and then to adesulfurizing treatment, substantially as specified.

3. The within-described improvement in treating skins, which consists in applying to the flesh side of the skin a liming compound, then removing the hair, then subjecting the unhaired skin to a sodium-sulfid bath, and then to a h'yposultite-of-soda solution, substantially as specified.

4. The within-described improvement in treating skins which consists in applying to the flesh side of the skin a liming compound, then removing the hair, then subjecting the unhaired skin to the action of asodium-sulfid bath, then to a hyposulfite-of-soda solution, and then to a desulfurizing treatment, substantially as specified.

5. The within-described improvement in treating skins, which consists in first applying to the flesh side of the same a compound 0E lime and arsenic, then removing the hair from the skin, then subjecting the unhaired skin to the action of a sodium-sulfid bath, then to a hyposulfite-of-soda solution, and finally to the action of a bath containing lime and arsenic, substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

SAMUEL K. FELTON, JR.

Vitnesses:

WALTER CHIsM, Jos. H. KLEIN. 

